Related Experiment Video
Updated: Jul 5, 2026

Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
[Intrathecal morphine in orthopaedic surgery patients. Optimised dose in patients receiving dipyrone]
1Klinik für Anästhesiologie, Intensivmedizin und Schmerztherapie, Klinikum Kassel GmbH, Mönchebergstr. 41-43, 34125, Kassel. gehling@klinikum-kassel.de
Introduction:
The influence of different postoperative doses of intrathecal morphine on the time of first opioid request by orthopaedic patients was investigated. The first choice analgesic was dipyrone and a maximum dose of 6 mg/day was allowed.
Methods:
A prospective, double-blind, placebo-controlled, clinical trial was conducted with 15 patients in each group receiving intrathecally either a placebo, 0.05 mg morphine, 0.1 mg morphine or 0.2 mg morphine in combination with a spinal anaesthesia with isobaric bupivacaine.
Results:
The number of patients without opioid requirement during the first 24 h after surgery were 3, 8, 14 and 14 in the placebo group and after 0.05 mg (p=0.128), 0.1 mg (p=0.0001) and 0.2 mg (p=0.0001) intrathecal morphine, respectively. The average time until first opioid requirement increased in a dose-dependent manner from 10.3 h to 23.9 h (p<0.0001).
Conclusion:
In orthopaedic patients with dipyrone as the primary analgesic, the addition of 0.1 mg or 0.2 mg morphine to spinal anaesthesia provided a simple long-lasting postoperative analgesia and the use of additional opioids could be avoided during the 24h postoperative period.
Related Concept Videos
Opioid Analgesics: Synthetic and Semisynthetic Opioids
Local Anesthetics: Clinical Application as Epidural Anesthesia
Since epidural anesthetics can be infused through an epidural catheter, all types of drugs, including short-acting ones, can be administered. Chloroprocaine and lidocaine are examples of short and long-duration anesthetics, respectively. Bupivacaine...
Drug Delivery: Parenteral Route
There are three primary parenteral routes: intravenous (IV), intramuscular (IM), and subcutaneous (SC). The IV route introduces the drug directly into the bloodstream, ensuring immediate action. The IM route...
Analgesia and Pain Management
Local Anesthetics: Clinical Application as Spinal Anesthesia
Opioid Analgesics: Morphine and Other Natural Cogeners